The present invention generally relates to cutting guides and, more particularly, manual plasma torch cutting guides that incorporate a spacer mechanism which serves as both a load bearing or spanning surface and a gap determinant device.
Cutting guides are generally known in the art. Many of the guides in use today were originally designed for gas torches and incorporate wheeled bearings or similar fixed structures that grip the head of a hand held plasma torch, hereinafter referred to as a plasma torch. The function of these designs are to steady the torch in one axis while being work supported, and similar designs have been adapted for use by those working in the art (i.e. U.S. Pat. No. 4,695,041 and the like). That approach, as well as others commercially available rely on having a surface that is both continuous and debris free to ensure a consistent cut, it is not ideal for cutting either expanded metals or metals with voids in and around the cutting path.
Similar approaches (i.e. U.S. Pat. Nos. 4,381,854; 4,391,433 and 2,813,710) incorporate a guide flange, guide bar, or other semi-rigid structural member, hereinafter referred to generally as a guide bar, upon which the torch head rests with or without the aid of a carriage attached to the head that limits the lateral movement. The guide bars are frequently secured to the work piece via magnets and as a result are limited in application to ferrous metals only. Other disadvantages are apparent to those skilled in the art, including among others a lack of rotational control that can lead to displacement of the torch head (i.e. U.S. Pat. No. 4,411,411).
Those approaches that use carriage style carriers often have a horseshoe- or u-groove (as in U.S. Pat. Nos. 6,620,373; 4,411,411; 4,391,433) to simply engage and ride on a guide bar. These particular designs are not desirable for use with a plasma torch, as the head must be clamped firmly in place. Also, should any rotational misalignment of the plasma torch handle relative to the direction of travel occur while cutting, these designs would bind—resulting in blow-back. It is normally desirable to maintain a smooth drawing action across a work piece while operating a plasma torch to provide a clean, consistent kerf width and therefore a precise cut. Particularly in the case of plasma torches, irregular movement causes blow-back into the torch head. Unlike standard gas operated torches, plasma torches are susceptible to fouling of the tips in that event, which in turn increases the consumable usage. Also, these known approaches allow heat generated by the cutting action to unduly affect the rigid member supporting the carrier—directly exposing the rigid member to the flame, or spark—thus warping it longitudinally and affecting the cut accuracy directly during operation of the guide.
Additional approaches known in the art incorporate a floating torch head (i.e. U.S. Pat. No. 4,549,725) that would be difficult to use with a plasma torch as it would require two hands for operation, one to enable the integral safety on the plasma torch and the other to manipulate the carriage assembly along the cutting path. Still other known approaches (i.e. U.S. Pat. No. 4,381,854) provide for no z-axis adjustment, and are thus limited in their use—primarily to particular materials of solid ferrous construction.
Finally, only a very few approaches (i.e. U.S. Pat. Nos. 4,549,725, and 6,620,373) incorporate any kind of work piece clamping or restraint that attempts to address the issue of misshapen stock which may encroach upon the plasma torch tip and result in its fouling. Some plasma tip designs (i.e. U.S. Pat. No. 5,856,647 and the like) have opted to adapt their plasma torch to ride directly on the work piece and as a result are frequently fouled by foreign debris on the work piece, or are impeded in their travel impeded by debris not excluding blown back slag.
Therefore, a need exists for a quickly deployable system that addresses the operational constraints of such devices as a plasma torch and does not suffer the shortcomings of existing designs.
The statements mentioned beforehand do not constitute prior art, but merely provide a background for the present disclosure.